Pardon my naivety and inexperience, but I am hoping someone can help explain something to me? I understand that wood expands and contracts with temperature and humidity, that part I get. But if with flooring we are so conscious of this property of wood why do we nail the flooring down every 6 or 8 inches to a structurally stable and non-flexing subfloor? How can the planks expand and contract when they are nailed down???

Thank you in advance.

Alan

Simply put they just do .. Anyway, we try to keep movement down thats the whole idea of being aware of temp and rh and moisture content. Thats why it's preferable to install after the hvac is up and running and the wood has acclimated and there is no outside source of excessive moisture under the floor. No need to reinvent the wheel here full trowel bostic best and blind nail just make sure the subfloor and material are within two percent moisture content. The only other safegard I have seen a few do and what Micky Moore at NOFMA told me to do on wider plank was to seal the back sides of the boards, it's a chore and am not sure its necceasary in your instance but it's not unheard of in cliamtes where they see big swings in rh in the home throughout the year.